1. Field of the Invention
The present invention relates to an apparatus for extracting usable energy from a thermal elastic wire. More particularly, the present invention is a power transmission device which accommodates the physical change rate of a thermal elastic wire as it changes phase to permit the extraction of usable energy from the phase transition. Still more particularly, the present invention is a power transmission which extracts and stores energy from a thermal elastic wire without overstressing the wire during its rapid shortening phase change. Specifically, the present invention is a power transmission which extracts and absorbs energy from a thermal elastic wire due to the wire shortening at a variable rate during phase change of the wire and outputs a smooth power stroke.
2. Description of the Prior Art
The use of energy transfer mechanisms in one form or another for the purpose of producing work from thermal elastic material transformations is known in the prior art. However, despite the numerous designs, structures, forms of apparatus, and variety of methods disclosed by and utilized in the prior art, which have been developed for the accomplishment of the specific objectives, purposes, and requirements of harnessing thermal elastic phase changes, the devices, machines, constructions, and methods which have been heretofor devised and utilized to accomplish these goals consist basically of familiar, expected, and obvious configurations, combinations, and arrangements of well known structural forms and apparatus. This will become apparent from the following consideration of the closest known and relevant prior art.
The inventor of the present invention is also the inventor of the Banks Engine, U.S. Pat. No. 3,913,326, issued Oct. 21, 1975, which was the first proven reliable thermal elastic wire powered engine. The Background of the Invention section of that patent sets forth in part the status of the prior art at the time of that invention. The “Summary of the Invention” section of that patent describes the thermodynamic working material as a thermally responsive memory material which is the same as used to power the transmission of the present invention.
An improved version of the Banks engine was patented in 1981 under U.S. Pat. No. 4,257,231, issued Mar. 24, 1981. The Banks engines are powered by thermal elastic wires which change phase when subjected to different temperature environments. The phase changes elongate and shorten the wires. By alternating the wire environments, work can be extracted from the wires under controlled conditions.
The thermal elastic energy power transmission contemplated according to the present invention departs substantially from the conventional concepts and designs taught and used by the prior art, and in doing so, provides an apparatus primarily developed for the purpose of overcoming the problems as described above, but it accomplishes the result in a different and improved manner for producing usable work more efficiently, conveniently, faster, and economically